ML20245A684
| ML20245A684 | |
| Person / Time | |
|---|---|
| Issue date: | 07/03/1984 |
| From: | Cunningham R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| Shared Package | |
| ML20245A615 | List:
|
| References | |
| FOIA-89-205 NUDOCS 8906220120 | |
| Download: ML20245A684 (3) | |
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APPENDIX B - Continued UNITED STATES OF AMERfCA NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR MATEttIAL SAFETY AND SAFEGUARDS WASHINGTON, D. C. 20555 ORDER MODIFYING CERTAIN LICENSES (EFFECTIVE IMMEDIATELY)
I Recently, the Nuclear Regulatory Commission (NRC) staff was notified by a licensee of the failure of a locking mechanism on a self-shielded irradiator which could have resulted in a radiation overexposure. ("Self-shielded" irradiators are designed so that the radioactive source remains in a shielded position at all times, both during storage and during irradiations. Therefore, the irradiators need not b6 placed in a shielded room.)
The irradiator is a J. L. Shepherd Mark I, containing about 6,000 curies of cesium 137. The unit is operated as follows: (1) With the source in its shielded storage position, the shielded door is opened, (2) materials to be irradiated are placed inside the irradiator chamber, (3) the shielded door is closed (4) the radioactive source is raised into the irradiation chamber.
l (5) after irradiation is complete, the source is lowered, and (6) the door is
- opened for removal of irradiated materials.
l The shielded door is interlocked so that it should not open when the f radioactive source is in the irradiation chamber. However, in the case '
i reported to NRC, the lock mechanism failed. In such a situation, an l operator who opens the shielded door with the source raised could be l subjected to substantial radiation exposure. The J. L. Shepherd Model 81-22 l irradiator employs an interlock similar to the Mark I.
i The NRC staff has examined the irradiator in question and confimed the l defect. Furthermore, a New York City inspector checking a J. L. Shepherd Mark I frradiator in New York reported a malfunctioning interlock system.
NRC and the Agreement States are studying the problem further to assess its generic implications. '
l Based on the foregoing, I have r.oncluded that the possibility of failure
! of locking mechanisms and/or mechanical timers on J. L. Shepherd Mark I and j Model 81-22 f rradiators represents a potential radiatio'n hazard warranting immediate preventive action pending further investigation. I have determined, l therefore, that the public health, safety, and interest require that the i restrictions on the use of such irradiators as prescribed in Section II of this Order should be made immediately effective.
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APPENDIX C - Continued j 1 II Accordingly, pursuant to Sections 81, 115 1, 162 o, and 182 of the Atomic Enei Act of 1954, as amended, and 10 CFR Parts 2 and 30 of the Commission's regulations IT IS HEREBY ORDERED, EFFECTIVE IMMEDIATELY, THAT: Each license that authorizes possession of byproduct material in a J. L.. Shepherd Mark I or Model 81-22 self-shielded irradiator is hereby amended to add the following conditions: (1) The J. L. Shepherd irradiator shall not be used unless'the licensee provides a calibrated and operable radiation survey meter or ~ room monitor for use with the irradiator. (2) The irradiator door shall not be opened until the operator has checked visual indicators to verify that the source has returned to its safe storage position. (3) Each r'oom monitor (a) shall be operable at all times when the irradiator is in use, (b) shall activate a visible and audible l alarm when radiation levels exceed 2 millirems per hour, (c) shall I be located to detect a'ny radiation escaping from the irradiator door, and (d) shall be located so that it is visible to the irradiator user when he is next to the irradiator. (4) If a room monitor is not installed, a survey meter shall be used l (a) to detemine the radiation level.at the irradiator door when the door is closed, and (b) to check for any increase in radiation levels each time the irradiator door is opened. In conducting such I checks, operators shall position themselves so as to minimize exposure to any radiation escaping from the open door. (5) If abnormal radiation levels or any malfunction of the irradiator
- are detected at any time, the licensee shall stop use of the
! irradiator and immediately notify the appropriate NRC regional office by telephone. - l l
- (6) The' licensee shall not attempt repair or authorize others to attempt I
repair of the irradiator'except as specifically authorized in a license issued by NRC. j III i ! Any affected licensee may request a hearing on this Order. A request ' for a hearing shall be submitted within twenty (20) days of the date of this Order to Mr. R. E. Cunningham, Director, Division of Fuel Cycle and Material Sa'ety, U. S. Nuclear Regulatory Commission, Washington, D. C. t 20555, with a copy to the Executive Legal Director, U. S. Nuclear Regulatory Commission, Washington, D. C. 20555. ANY REQUEST FOR A HEARING SHALL NOT STAY THE IMMEDIATE EFFECTIVENESS OF THIS ORDER. i s 1 10.9-24 i-wwnmvnr,wwvv-~ w ~ ~ ;mryyrymvayn myy gggy;3 ;g
1 ./ ,. APPENDIX B - Continued i [ l IV
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If a hearing is requested, the Comission will issue an Order designating the time and place of any such hearing. If.a hearing is held the Issue to be considered at such a-hearing will be: Whether, on the basis of the matters ; set' forth in Section I and II of this Order, this Order should be sustained. FOR THE NUCLEAR REGULATORY COMMISSION
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Richard E. Cunningham, Director Division of Fuel Cycle and 1 Material Safety Office of, Nuclear Material Safety and Safeguards Dated at Bethesca, Maryland this 3rd day.of July.1984 l I l i I l l I e x g 10.9-25 i W.r_** y v s l s ~2:6 IJ ,"? MAWy@:'".mTW_C.RKTyG_=Y.- * ~' T n""'ni:!: .,' " ~7;Q'(;Eq%',*r"gM'"[( q'?R-[27t*M
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. SSINS NO.: 6835 I IN 85-01 ;
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1 . UNITED STATES NUCLEAR REGULATORY COMMISSION ) 0FFICE OF INSPECTION AND ENFORCEMENT J l WASHINGTON, D.C. 20555 January 10, 1985 J IE INFORMATION NOTICE NO. 85-01: CONTINUOUS SUPERVISION OF IRRADIATORS . Addressees:
'll licensees possessing irradiators that are not self-shielded and contain more than 10,000 curies of radioactive material.
Purpose:
This.information notice is provided to alert recipients of a potential safety hazard and violation of NRC license requirements which can arise if licensees do not provide continuous supervision of large irradiator' operations. "Large" irradiators are those which contain more than 10,000 curies of radioactive material and which are not self-shielded. Although proper supervision and security also is important for smaller irradiators, they are not the subject of this notice. ( ) It is expected that licensees will review this notice for applicability to l their facilities, if appropriate, to preclude a simi.lar problem occurring at their facilities. However, suggestions contained in this information notice do not constitute NRC requirements; therefore, no specific action or written response is required. Description of Circumstances: Some large irradiators operate 24 hours per day. Recently a case came to our i attention in which an irradiator was left operating overnight totally unattended. l The irradiator license specifically required the physical presence of a fully l trained supervisor whenever the irradiator was in use.' This provision of the l license is consistent with NRC policy and good safety practice that large irra-L diators should be continuously attended by a fully trained supervisor except ! when the radioactive sources are secured in their safe storage position. l Compliance with that requirement assures that a qualified individual is i ! immediately available to respond to emergencies or other problems. Note that l 10 CFR 20.203(c)(6) requires that large irradiators must be equipped with entry
- control devices and alarms to make an individual attempting to enter the exposure area aware of the hazard and to alert at least one other individual l who is familiar with the irradiator arid prepared to render or summon assistance.
l The NRC is closely reviewing this matter during inspections and licensing ! actions. Host irradiator licenses explicitly state that a trained person must be physically present whenever the irradiator is being used. The NRC regional office will contact separately any irradiator licensee whose license may not be clear with respect to physical presence. ' 850a0704olm* N .b . _..d _ , . ' a [ _. . . t. *
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. SSINS No.: 6835
. IN 87-29 J la r[
UNITED STATES g.1 NUCLEAR REGULATORY COMMISSION ,
'l% W*a 0FFICE OF NUCLEAR MATERIAL SAFQY AND SAFEGUARDS WASHINGTON, D. C. 20555 kW June 26, 1987 NRC INFORMATION NOTICE NO. 87-29: RECENT SAFETY-RELATED INCIDENTS AT LARGE IRRADIATORS l Addressees:
All NRC licensees authorized to possess and use sealed sources in large irradiators. -
Purpose:
This notice is being issued to inform recipients of recent safety-related l incidents at large irradiators, which could have been prevented by proper management actions and attention to preventative maintenance programs. It i is suggested that recipients review this infonnation and their procedures i and consider actions, if appropriate, to ensure both proper preventative maintenance programs and proper management actions at their facilities. I
) However, suggestions NRC requirements; therefore, contained no specific in this Infonnation action Notice'do tir written response not constitute is required.
l' Description of Circumstances: ,
- A description of each of six events is provided in Attachment 1. In sunenary, I these events included
l o hose failure resulting in a leak, failure to report the incident to NRC, i and deliberate cover-up of this incident when NRC tried to investigate. leading to company fines and personnel probation; l o intentional bypass of safety interlocks, resulting in license suspension i and other enforcement actions by NRC; s i o improper pipe routing and inadequate piping material, which broke and
- caused partial loss of pool water; l
o source unable to retract to its fully shielded position, due to a frozen solenoid valve; ! o a stuck source plaque, due to failure to promptly replace a frayed lift - ) cable; and l l o a stuck source plaque, due to interference from the product carriers and shroud.
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6*' - IN 87 29 June 26, 1987 Page 2 of 2 l' ,' q Discussion: These incidents illustrate a failure by management to assure that proper safety and mai'ntenance procedures are followed. It is suggested that super-visory personnel, particularly the Radiation Protection Officer and maintenance personnel, be reminded of their responsibilities to assure safe operation at
.their facilities. The incidents discussed in Attachment I demonstrate the l
L importance of:. 1
- 1. prompt reporting of incidents to the NRC, as required by regulations or Ifcense conditions
- 2. . safety training and periodic retraining of personnel l 3. not bypassing interlock systems or other safety systems
- 4. attention to proper plumbing installation and use of appropriate piping material -
- 5. proper maintenance of cables, carrier systems, and other components that could prevent radioactive sources from being retracted to a shielded position.
No specific actions or written response is required by 'this Information l Notice. If you have any questions about this matter, please contact the Regional Administrator of the appropriate NRC regional office or this office. l- J i
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RichardE.Cunningham,Iirector (' Division of Fuel Cycle. Medical, Academic, and Consnercial Use Safety Office of Nuclear Material Safety l' and Safeguards Technical
Contact:
Bruce Carrico, HMSS (301) 427-4280 Attachments:
- 1. Events That Occurred at Large Irradiator Facilities
- 2. List of Recently Issued NRC Information Notices l
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Attachment 1' IN 87-29 June 26, 1987 EVENTS THAT OCCURRED AT LARGE IRkADIATOR FACILITIES
'I.: While the licensee was attempting to decontaminate pool water because of a-leaking source, a hose on a filtration system ruptured. Contaminated
-pool water was then pumped onto the facility floor and leaked outside into the surrounding soil. The licens. Y led to report the incident to NRC, and made deliberate efforts to prevei.6 NRC's discovery of this incident.
Subsequently, the licensee was indicted by a Federal Court. - A convictior, resulted in a $35,000 fine for the company and two years probation for a management-employee. . Licensee failure to make required reports prevents the NRC from performing its radiological health and safety function and. from making a timely assessment of the nature and severity of an incident.
- 2. - A licensee deliberately bypassed the safety interlock systems. The NRC subsequently ' learned that licensee personnel had willfully violated requirements, and that senior licensee management knew, or should have known, of these violations. When NRC attempted to inspect and investigate L
these suspected violations, senior licensee management knowingly provided false information to the NRC. Subsequent enforcement action included suspension of the license. 1 L -3. A water line fractured in the pool circulation system which resulted in ! the loss of 5 feet of pool water. The line break led to a loss of l ) shielding water because the intake and ootlet pipes were misaligned j / during maintenance. The pipe break appears to have occurred because the pipe was made of polyvinyl. chloride, designed for cold water, rather I than for the heated water temperatures typical for the irradiator. The l_ piping was replaced with polypropylene pipe, o L 4. A night shift operator noticed that the travel time for the source to reach the fully unshielded position was excessive. After completing the next phase.of irradiation, the source would not retract to the fully shielded pasition, even using emergency equipment. The operator discovered that the solenoid valve, that was supposed to retract the source to a shielded position, was frozen due to weather conditions. The valve was I in a room above the irradiator facility. The operator went there-and turned on a room heater to thaw out the valve so that it would operate. The operator violated license requirements to (1) notify the Radiation Safety Officer (R50) that the source had not returned to its shicided position because of the frozen valve, and (2) obtain RSO perinission to L enter and heat the room housing the valve. }- A licensee had identified a frayed lift cable a few days previously, but ! 5. L instead of imediately replacing the cable, the licensee decided to wait j; for scheduled maintenance. The cable jansned and froze the source plaque l in'a less than fully shielded position. Employees cut the cables and let l the source plaque free-fall into the pool. The incident could have been prevented by replacing the frayed cable insnediately, and selecting cable material with fray-resistant qualities. l- ' I I L _
- 6. A source plaqu2 became stuck in the expos::d position. Conveyors stopped, the source DOWN light came cn, but cell radiation levels remained high.
Cable slack data indicated that the plaque was stuck about five and a half feet down from its full-up position. The RSO attempted some raising and The lowering maneuvers, but the plaque then stuck in a full-up position. RSO, able to run the product containers out of the cell, saw some were The RSO notified a State Inspector, who arrived misaligned on the in the afternoon. carrier.It was determined that the plaque cable was off its pulley. The bottom of a splice in the cable was resting on the lip of the tube leading to the. cell. After the cable was set on its pulley, the cable was guided through the tube, and the plaque was lowered, until it caught again. A borrowed radiation-resistant camera arrived the next morning. An adequate view of the plaque was obtained by midnight. Apparently the stationary aluminum shroud between product containers and plaque had been deflected l The plaque was carefully raised and dropped and caught to break theon the plaque frame.On the second try, the plaque broke free and dropped jam.
'into the pool. Analysis revealed that a product t.ontainer had probably tipped onto the shroud, causing interference with the plaque.
This incideht was apparently caused by in' adequate design of the shroud. This led to the shroud deforming, which interfered with plaque motion. Inadequate maintenance contributed to theAproblem. The cable should have been replaced instead of spliced. few months later, the entire source hoist mechanism failed and had to be replaced. This failure oc-curred when the source plaoue was submerged.
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